Cut lobster in half lengthwise. Place halves shell-side up in a large saucepan and 2 tbsp of butter and the mushrooms. Saute until the shells turn bright red or about 5 minutes. Set aside. In a separate saucepan, add shallots and wine, and boil over medium heat until reduced by half. Add the chervil, the rest of the butter, and the wine/shallot reduction to a blender and combine until smooth. Serve by removing the lobster meat from the shells and place on a bed of the sauteed mushrooms. Pour the sauce all around.